The development and early clinical testing of the ExPEC4V conjugate vaccine against uropathogenic Escherichia coli

Laboratory development and early phase I testing were successful, as the vaccine candidate emerged with strong safety and immunogenicity profiles. The clinical trial was ultimately underpowered to detect a significant reduction in vaccine-specific E. coli UTI, though it showed a significant decrease in the incidence of UTI caused by E. coli of any serotype. We discuss the findings, including the lessons learned.